Extraction of asphalt



March 27, 1934. A, B, ALVEY AL 1,952,647

EXTRACTION 0F ASPHALT Filed Jan. 10, 1931 fizz/6W5: dZo Sit/55 (ZZz/6' 63m Halve Patented Mar. 27, 1934 UN ED STATES EXTRACTION OF ASPHALT Aloysius B. Alvey, Glenn H. Alvey, and Ernest A. Young, San Antonio, Tex., assignors to Uvalde Rock Asphalt Company, San Antonio, Tex., a corporation of Texas Application January 10, 1931, Serial No. 507,852

1 Claim.

The invention relates to the art of extracting hydrocarbons from their associated rock or sand, and hasreference more particularly to a process and preferred embodiment of apparatus therefor for extracting relatively pure asphalt from bituminous rock.

Heretofore in most instances the separation or extraction of asphalt and such other hydrocarbons'..as are associated with rock or sand has adopted either heated water or some solvent as the active separating medium.. Heated water has been used successfully only where the hydrocarbon is lighter than water and is fairly soft inconsistency. In a few instances the hydrocarbons are distilled off by heat, and in cases wherethe rock contains an excessive amount of bitumen, heat has been used to liquefy the bitumen so that the same can be drawn off by suitable means. The principal processes used for extraction have used solvents of various kinds to effect the separation. These solvent extraction processes have however, been costly because in the first place, the cost of equipment was high, the operation was slow, and second, because no means were provided for the complete and economical recovery of the solvent left in the waste rock afterthe bitumen had been extracted.

To this end an object of the present invention is to provide a process for the extraction of asphalt from bituminousrock which will overcome' the disadvantages above mentioned, which will employ simplified equipment and which will constitute a continuous process rather than a batch process thereby materially speeding up the operation. The raw materials are received in one end ofthe extractor of the present invention and are discharged at the other end in one continuous stream, so that the cost of equip-' of the solvent from the waste by a subsequent treatment of the same.

A yet further object of the invention is to provide a process of the kind described which will -accomplish the recovery of the solvent in such solvent, but also eliminating the. cost of recovery a manner that the process materially aids in the extraction of the bitumen and permits a more complete extraction of the bitumen from its associated rock or sand.

With these and various other objects in'view, the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawing and claim appended hereto.

In the drawing, which illustrates an embodiment of the device and wherein like referencecharacters are used todesignate like parts The figure is a diagrammatic view showing the arrangement of the various apparatus required for the process constituting the present invention.

In the preferred embodiment of apparatus disclosed the centrifugal separator 10 consists of a funnel shaped container 12 having connection at its bottom to a discharge pipe 14 and having its upper end. suitably enclosed by means of a cone shaped housing 16,. Associated withthe housing 16 and suitably secured to the periphery of the container 12 is a cylindrical container 18 to which is suitably connected pipes 20. The container 12 provides a chamber 22 within which is positioned a supporting member 24 for supporting the gear housing 26. Rotatably mounted within the gear housing is a vertically disposed shaft 28 having gears 30 suitably secured thereto and having fixedly secured to its upper end a cone shaped disc 32. Also rotatably mounted in housing 26 is a second shaft 34 having gears 36 meshing with the gears 36 on shaft 28 and to which is secured the electric motor 38 providing the driving means for the same. Thus, through operation of motor 38, disc 32 is adapted to be rotated at a high speed for purposes to be described. Positioned in the housing 16 and spaced between the wall thereof and the disc 32 is a screen 40 having-openings sufficiently small to prevent finely crushed rock and sand from passing through, but which will allow the passage of liquids.

Associated with the discharge pipe 14 is a valve 42 having a construction such that operation of the valve will allow the discharging of the waste material from the pipe but which will prevent the leakage from chamber 22 of any gases. Surrounding the pipe 14 immediately above the valve 42 is an evaporator or dryer 44 for heating the waste rock and sand located within the discharge pipe 14 to volatilize any solvent that might remain in the same. Connected to the upper end of the centrifugalseparator 10 is an inlet pipe 46 connected to the cylinder 48 within which is adapted to operate the screw conveyor 50. Con nected to one end of the cylinder 48 is a hopper 52 for holding the bituminous rock previously pulverized to a size most convenient for extracting purposes. The valve 54 controls the admission of the pulverized rock to the screw conveyor and similar to valve 42 is constructed to prevent the escape of the gases from the cylinder 48. Connected to the cylinder 48 at a point in the vicinity of the inlet means described is a pipe 56 provided with valve 58, the pipe in turn having connection to the condenser 60 containing the supply of solvent. The solvent is thus conducted to the cylinder and admitted to the same simultaneously with the pulverized bituminous rock so that the cylinder forms a mixing chamber in combination with the screw conveyor, whereby the rock and solvent are thoroughly mixed and brought into intimate contact prior to being delivered to'the centrifugal separator 10.

The extraction process of the present invention contemplates the use of a commercially available solvent of the hydrocarbon being extracted. In some instances gasoline, naphtha and similar solvents derived from petroleum will be found most suitable, while in others solvents derived from coal tar products will be found best. In still other cases such solvents as are derived from wood or which are manufactured chemical solvents, such as carbon disulphide, carbon tetra" chloride or acetone will be found to be satisfactory. It has been found preferable that the solvent have a close range of distillation, a low boiling point and a low cost.

A still, indicated by 62, is suitably connected to the discharge pipes 20 for the solvent by means of the pipe 6% and has also suitable connection to the condenser 60 through means of the con necting pipe 66 having located intermediate its length, any suitable fan or blower 68 to insure the circulation of the gaseous solvent in the right direction.

In the operation of the apparatus the bituminous rock or sand, previously pulverized to a size suitable for handling and extracting, is placed in the hopper 52 and fed at a predetermined rate through valve 54 into the mixing chamber simultaneously with the admission of the solvent from pipe 56, admitted at a predetermined rate determined by the amount of rock being fed, the kind of rock and the kind of solvent. The spiral conveyor is adapted to be slowly rotated by any suitable means to cause intermixing of the rock and solvent which results in the bitumen becoming dissolved in the solvent. The mixture is then discharge through pipe 46 into the centrifugal separator.

It is, of course, understood that disc 32 of the separator is rotated at high speed and as the mixture slowly works its way past the cone shaped disc the solvent, which has dissolved the bitumen out of the rock, will be thrown outward passing through screen 40 and collecting in the chamber 18 provided for the purpose. The rock not being able to pass through the screen 40 will gradually work its way downward until the same is discharged into the chamber 22, the rock in the meantime, however, becoming dryer and its temperature becoming lower by reason of the evaporation of the solvent. Passage of the mixture through the centrifugal separator therefore results in a separation of the rock which is collected in the tube 14 and of the solvent having the bitumen in the solution, and collected in the container 18 from which it is drawn oil through pipes 29 and 64 and collected in the still 62.

The waste rock or sand in the tube 14 is thoroughly dried by the dryer 4.4 which causes any solvent adhering to the rock to evaporate and when the rock has been thoroughly dried it is removed from the chamber through the discharge valve 42. The evaporated solvent will work its way up into the centrifugal separator and in doing so will serve to materially aid in the extraction of the bitumen remaining in the rock. This gaseous solvent helps the extraction in two ways, first. by furnishing a moist atmosphere in the extractor, thereby preventing the solvent from drying out too fast, and second by condensing on the particles of rock from which the solvent and bitumen have been removed, since these particles have been cooled by the evaporation of the solvent as it is forced out of the rock. by centrifugal force. The solvent thus condensed, together with the gaseous solvent combines with the bitumen in the waste rock makingthe same liquid and allowing the centrifugal separator to separate the same from the waste, whereupon it is collected in the container 18. The still 62 containing the solution of solvent and bitumen is subjected to heat in sufficient quantities to evaporate the solvent, whereupon it will be conducted through pipe 66 by means of the fan 68 to the condenser, where it will revert to its original form for further use.

The process is continued until the extracted bitumen becomes concentrated in the still 62, then by use of suitable pipe connections, not

shown, the still is disconnected and substitutedin its place is a similar still which, for the sake of clearness, can be designated 162. The proc ess is then continued using still 162 instead of the still 62. Heat is applied to the latter still until all the solvent is evaporated leaving a 'hot liquid mass of pure bitumen, which can be drawn ofi at will through valve 70. In some instances it will be found advantageous, in securing a more perfect recovery of solvent in less time to arrange to operate these stills under a partial vacuum. Also it has been found advantageous to heat the rock asphalt and the solvent before introducing them into the centrifugal machine.

The process described above will not completely extract all the bitumen from the rock but when used for extracting the bitumen from most bituminous rocks the extraction will be sufficiently complete to make the process commercially profitable. Should it be desired to make a more perfect extraction of the bitumen, it will be mereiy'necessary to use two continuous-centrifugal separators set up in tandem so that the discharged material from the first separator will be delivered to the second separator. Before introducing the waste to the second separator, it is desirable to add additional solvent thereto which can be added by means of a mixing chamber similar to the cylinder 48 and conveyor 50 as described. A procedure which "has been found most practical and eflicient is to feed fresh solvent to the mixing chamber ofthe second centrifugal separator into which the waste from the first machine is being fed and instead of using fresh solvent on the first or-upper separator to convey the solvent and dissolved bitumen discharged from the second or lowerseparator to the mixing chamber of the first. In other words, fresh solvent is used in the second machine f r extracting the bitumen that remains in the waste discharged from the first and thenits the solvent containing the dissolved bitumen is conveyed to and used for extracting the major part of the bitumen in the asphalt or bituminous rock that is fed into the first machine.

It is to be understood that we do not wish to be limited by the exact embodiment of the device shown, which is merely by way of illustration and not limitation, as various and other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claim.

We claim:

Means for extracting bitumen from bituminous rick, comprising a mixing chamber and means to feed crushed bituminous rock and a 

